Study on air pollution in Beijing's major industrial areas using multielements in biomonitors and NAA techniques

Three kinds of plant leaves, Chinese white aspen, arborvitae, and pine need les, have been sampled from the Yanshan Oil refinery complex, the Capital I ron and Steel Factor): and Badachu, a control area in Beijing, as biomonito rs for air-pollution studies. Each sample was divided into two parts, washe d, and unwashed. Thirty-one trace elements (As, Au, Br, Ca, Cd, K, La, Lu, Mo, Na, Sb, Sm, U, W, Yb, Ba, Ce, Co, Cr, Cs, Eu, Fe, Hf, Hg, Rb, Sc, Se, S r, Ta, Tb, Th, and Zn) have been determined by using the relative and the K -o methods of instrumental neutron activation analysis (NAA) techniques. Th e results indicated the following: (1) The concentration of trace elements in unwashed samples are much higher than these in washed samples; (2) the a rea around Capital Iron and Steel Factory is heavily polluted, and the Yans han Oil refinery complex area is moderately polluted; (3) Chinese white asp en is a good biomonitor in particular seasons and pine needles are better t han arborvitae for yearly monitoring; (4) elements As, Cd, Hg, Co, Rb, Sb, W, and Zn are highly absorbed by Chinese white aspen. Pine needles are sens itive for the absorption the elements Br, Cr, Cd, Fe, Sc, Cs and rare earth elements, but arborvitae is very sensitive for the absorption of Sr.